Solventless C–C Coupling of Low Carbon Furanics to High Carbon Fuel Precursors Using an Improved Graphene Oxide Carbocatalyst

Abstract

Graphene oxide, decorated with surface oxygen functionalities, has emerged as an alternative to precious-metal catalysts for many reactions. Herein, we report that graphene oxide becomes superactive for C–C coupling upon incorporation of a highly oxidized surface associated with Brønsted acidic oxygen functionality and defect sites along the surface and edges. The resulting improved graphene oxide (IGO) demonstrates significantly higher activity over commonly used framework zeolites for the upgrade of low-carbon biomass furanics to high-carbon fuel precursors. A maximum 95% yield of C15 fuel precursor with high selectivity is obtained at low temperature (60 °C) and neat conditions via hydroxyalkylation/alkylation (HAA) of 2-methylfuran (2-MF) and furfural. Coupling of 2-MF with carbonyl compounds ranging from C3 to C6 produces precursors of carbon numbers 12 to 21 with a high yield. The catalyst regains nearly full activity upon regeneration. Extensive microscopic and spectroscopic characterization of the fresh and reused IGO carbocatalysts indicates that defects and the enhanced oxygen content are strongly correlated with the high activity of IGO. Density functional theory calculations reveal defects at carbonyl sites as suitable Brønsted acidic oxygen functional groups. A plausible reaction mechanism is also hypothesized.

Selectivity tuning over monometallic and bimetallic dehydrogenation catalysts: effects of support and particle size

“…[9][10][11][12][13][14][15] However, the production of higher value-added products in the jet and diesel range requires the lengthening of the molecular carbon chain length. To achieve this, a variety of C-C bond formation strategies has been investigated, such as ketonization, 16,17 furan condensation 18,19 and aldol condensation. 20,21 Of particular interest is the tandem dehydrogenation-aldol condensation reaction.…”

Hydro(deoxygenation) Reaction Network of Lignocellulosic Oxygenates

“…Alternative routes are also developed for making furan derivatives capable of producing branched alkanes and cyclic branched alkanes required for low‐temperature fuel applications, such as for modern aircrafts and supersonic jets. An acid‐catalyzed HAA/alkylation of aldehydes, such as FUR with 2‐methylfuran (2‐MF), offers a series of high‐carbon furans with branching due to the nature of condensation processes, which can be carried out under solvent‐free conditions with high selectivity for the desired products at about 60 °C . The selectivity of HAA of 2‐MF and FUR is efficient by using the improved graphene oxide (IGO) catalyzed method under solvent‐free conditions .…”

3-Bromopyridine-Heterogenized Phosphotungstic Acid for Efficient Trimerization of Biomass-Derived 5-Hydroxymethylfurfural with 2-Methylfuran to C21 Fuel Precursor

“…However, the shortcomings are also obvious; for example, (1) the acid catalyst H 2 SO 4 is harmful to the environment, and (2) the homogenous catalyst would be lost and could not be reused after one reaction cycle. In 2017, Dutta et al [25] came up with a modified graphene material to catalyze HMF and 2-MF into MMBM under 63°C for 12 h. In 2018, Wang et al [26] and Gebresillase et al [27] also prepared Sn-K-10 and KCC-IAPSO 3 H as acidic catalysts for the condensation of 2-MF with acetic anhydride and 2-MF with furfural, n-butyraldehyde, or 2-pentanone into C 17 or C 14 -C 15 fuel precursors under relatively mild conditions, respectively. These reaction systems can achieve the conversion of biomass platform molecules into long-chain molecule precursors by using acid catalysts, while the main disadvantage is that the catalyst preparation methods are too complicated and the cost is too high.…”

“…A C 21 compound named 5-(bis(5-methylfuran-2-yl)methyl)-5′ -methyl-2,2′-bifuran (MMBM), which is derived from condensation of biobased 2-methylfuran (2-MF) and 5hydroxymethylfurfural (HMF) with an acid catalyst, is a cost-effective and promising biochemical for producing drop-in fuels [21] and can be directly employed to increase the fuel combustion efficiency. In addition, after hydrogenolysis, MMBM can be used as high-quality fuels (Scheme 1) [22], such as aviation [23,24] and diesel fuels [25]. Therefore, the production of such biomass-based C n compounds for highquality biofuels has attracted the researchers' interests in recent years.…”